ACIDS and BASES

• Target: I will be able to define what makes something an acid or a base. I will be able to tell on a pH scale if something is an acid or a base. I will be able to describe an indicator.

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Acids

• Taste sour• React with metals• Turns blue litmus

paper red.

• Examples: vitamin C (and other vitamins), vinegar, aspirin

• Taste bitter• Feels slippery• Turns red litmus

paper blue.

• Examples: cleaners, soaps, drain cleaner, cement

Bases

Indicator: a compound that changes color when in contact with an acid or a base.

Acids

• When in H2O, acids produce positive hydrogen ions (H+)

• HCl H+ + Cl-

• The stronger the acid, the more H+ there are.

• When in H2O, bases produce negative hydroxide ions (OH-)

• NaOH Na+ + OH-

• NH3 + H2O NH4+ +

OH-

• The stronger the base, the more OH- there are.

Bases

pH Scale

• pH stands for potentz (potential to be) Hydrogen

• It is a scale from 0 to 14• 7 is neutral• Low numbers are acidic (a high

concentration of H+)• High numbers are basic (a low

concentration of H+ and high OH-)

When an acid is mixed with a base, they neutralize each other.

The products of this reaction are a salt (any ionic compound that is the result of a neutralization reaction) and water.

http://phet.colorado.edu/simulations/sims.php?sim

=pH_Scale